Method and apparatus for reducing correlated errors in subband coding systems with quantizers
CA 2106440 C · Owner: American Telephone And Telegraph Company · Inventors: Kovacevic, Jelena
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method and apparatus for reducing correlated errors in subband coding systems with quantizers is disclosed. A subband coding system comprises aplurality of subband analysis filters to divide the frequency spectrum of the input signal into subbands, individual subband quantizers for coding each subband by apreselected number of quantization levels corresponding subband decoders and, subband synthesis filters. The transfer function of each of the subband synthesis filters is advantageously determined based on the transfer functions of the subband analysis filters as well as on the characteristic of the quantizer used to code the corresponding subband. Specifically, the synthesis filter …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed September 17, 1993 and granted November 18, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 17, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 17, 2015.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.